Process of making fireproof conductors.



AMANDA NI-LOUGE-E, OF BOSTON, MASSACHUSETTS.

PROCESS OF MAKING FIREPROOF CCNDUOTORS.

Specification of Letters Patent.

Patented Jan. 9, 1906.

. Application filed May 23, 1904. Serial No. 209,191.

To all whmn it may concern.-

Be it known that I. AMANDA l I. Loosen, a citizen of the United States, and a resident of Boston, in the Commonwealth of Massachusetts, have invented an Improvement in Processes of Making Fireproof Conductors, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts. i

The difficulties attending the use of electric wires have thus far proved practically insurmountable, the result being that notwithstanding the many and persistent efforts to provide a practical conductor meeting the requirements of the underwriters and the trade such a wire has yet to be produced. For meeting all the requirements of use and doing away with a separate conduit it must not only have high insulation, be fireproof, waterproof, nailproof,flexible,durable,and not liable to change its character by age, but it must be small in size, moderate in cost, convenient to handle, and present a fair appearance.

In a concurrently-filed application I have disclosed and claimed a protected conductor for meeting all the above requirements, and the present application relates to the method or process of making said protected conductor, the object thereof being to render the conductor as nearly perfect as possible at all points throughout its structure in respect not only to insulation, (which has been the main object aimed at heretofore) but also in respect to fireproof qualities, electrolysis-proof exterior, durability, flexibility, permanence of character, &c.

In carrying out my invention I first coat the electric wire with a compound having great strength and extremely-high insulation, preferably increasing in fire resisting qualities from the center outward, and surround this coating with a fireproof jacket permeated with a special compound for rendering it still further fireproof and impervious, and about this jacket I provide a plastic layer of fireproof and vulcanizable ingredients, in the outer surface of which is embedded a wire covering having a coating of special materials applied in such a manner as to become practically a part of said covering, the latter having successive applications thereof, and finally a second and in some instances a third covering of wire and coating serve to render the article adapted to the most exacting requirements of underground and other construction, the whole being vulcanized and rendered as nearly integral and homogeneous as possible.

The various steps pursued in practicing my process will be set forth at length in the following description, reference being had to the accompanying drawings, illustrative thereof, and the various limitations of the invention will be further defined in the appended claims, also forming a part of this specification.

In the drawings I have shown a series of side elevations representing the various steps of manufacture followed out according to my process, Figure 1 showing the initial stages of the process, Fig. 2 the next step, Fig. 3 representing the treatment applied to the asbestos or fiber covering. Fig. i represents the application of the successive coatings of compound to the asbestos covering. Fig. 5 represents the wire jacket and its covering both inside and outside. Fig. 6 represents the second wire jacket and Fig. 7 the third wire jacket and the process of their treatment and coverings. Fig. 8 represents the successive steps followed in applying my invention to the manufacture of a cable.

Referring to Fig. 1, where the invention in its simpler embodiment is shown, let a represent a copper wire or other electrical conductor. This is provided with a covering or coating at, composed of rubber and fireproof material, so as to combine the very best insulation with proper fireproofing to render flaming practically impossible. The fireproofing is not secured by applying an external coating, but is formed as a part of the compound, the ingredients being mixed with the rubber or other highly insulating material and applied so that the pure rubber comes adjacent to the wire and the fireproof ingredients increase in amount outwardly. This compound may be composed of the ingredients set forth and referred to in my Patent No. 717,009 and may be applied in the manner therein mentioned. For the best results and the highest grade of conductor I prefer, however, to employ a compound consisting of rubber, zinc, sulfate of aluminium, and sufiicient sulfur for purposes of vulcanization, and even .in the cheaper grades to employ sulfate of aluminium in connection with the other ingredients such as are mentioned in my patent aforesaid in connection with oxidized oils and hydrocarbons. I have found sulfate of aluminium superior for my present purpose, as

it is readily handled and superior in its fireproofing effects, especially when used in con nection with the process herein set forth. The covering a is then provided externally with one or more thin coatings or dippings (o of an extremely fireproof compound selected, preferably, from the above-mentioned ingredients, (which, it will be understood, may be compounded so as to make the fireproofing or the insulating or the flexible characteristics predominate according to the various proportions used,) and then a covering a of asbestos or woven fiber saturated with fireproof substance, preferably with the aforesaid sulfate of aluminium, is braided (or wound as a tape) tightly in place. All the meshes of this braided jacket (4 and the fiber itself are completely filled with the aforesaid compound applied in a thin liquid form, with the result that the jacket is permeated both inside and outside thereof. The covering a is then dipped sufficiently to coat it, as indicated at a", with a comparatively thin and vulcanizable coating of high fire resistance and flexible qualities, and then a considerable body (0 of the special compound above mentioned is applied and while yet plastic a covering of Wire a is woven or braided thereon tightly, so as to embed itself in the coating (i The wire covering (6" having been tightly and compactly applied, as stated, it is dipped in the fireproof compound above mentioned at a high heat, the result being that the metal is caused to expand or open its pores, so that when it cools, and therefore contracts, the coating is drawn into the metal and becomes not merely applied thereto, as in the case of a paint, but in a sense incorporated therewith, and as the compound is more or less elastic it not only is incorporated with the separate strands of wire, but fills the interstices and unites with the plastic compound a so that the various layers of compound and wire are in no sense separate or properly recognizable as distinct layers, but they are united in as nearly a homogeneous structure as it is possible to obtain. The dipping of the conductor as thus far constructed is repeated several times to get the desired thickness until a considerable body or coating a is provided, and then While the latter is still somewhat plastic a second covering of Wire (L8 is tightly Woven or braided in place, being then dipped in a hot bath of the rubber and fireproof compound, as indicated at a", so as to become as nearly as possible incorporated with the wire and also so as to unite With the coating a and completely fill and solidify the meshes and unevenness of the Wire covering (6 especially on the outer surface thereof. Successive clippings, or it may be a thicker mass or bath of the compound, are then applied, as indicated at a and on this coating an outside covering of Wire a is applied in the same manner as before stated. On this last-mentioned covering of wire a a heavy outside coating a is applied in successive hot dippings until the desired thickness of outside covering is obtained.

All the successive baths or solutions of the compound in its different states of fluidity and composition contain suitable vulcanizing agents in proper proportions to accomplish the desired results, as above set forth, and acco rdingl y the next step after the conductor has been built up, as above explained, is properly to vulcanize it as a whole, so that it all becomes, to all intents and purposes, a one-piece article, none of the layers being capable of removal or separation either accidentally or intentionally from the rest of the structure. When several coverings of wire are used, I prefer to have the first covering a woven more coarsely or loosely, so that it will permit the outside and inside layers of compound to unite more directly and firmly with each other, and I prefer to have the layer (03 composed of fine wire, so that the strands may rest as snugly and tightly against each other as possible. I also prefer to employ different kinds of metal for these successive layers of wireas, for instance, the outside layer a may be composed of steel wire for giving great strength and various other kinds of metalsuch as copper, aluminium, iron, brass may be employed in the other layers as may be'required for giving increased flexibility or lightness or for decreasing the expense, &c.

In applying my invention to the construction of heavy multiconductor underground cables, as indicated in Fig. 8, I follow the same general plan of construction. Having first constructed the individual conductors as above explained, I mount them in proper relation to each other, as indicated at 7), Fig. 8, where two x are shown, and surround them with a proper amount of compound 6, the same as above described in connection with the layer a. This compound having adjacent the center of the cable and about the individual conductors extremely-high insulation and increasing in fireproof ingredients as it recedes toward the circumference, the outside thereof at 6 having a relatively thin layer of the most highly fireproof character. It will be understood that the compound can be varied to suit different requirements simply byincreasing or decreasing the proportion of fireproof ingredients with relation to the insulating ingredients and vulcanizing ingredients, &c., as is more fully stated in my patent above mentioned and the others therein referred to. About the layer 1/ I apply a heavy layer of thick compound I)", over which is woven a loose jacket of wire 6'', and to this covering is applied under heat a series of thin coatings, as indicated at b", and then a coating of thick compound I) for receiving a line tightly-braided jacket 0 which again is coated under heat, as indicated at t, and a thick coating is next applied to receive awire jacket 6 The jacket 6 is composed of quite coarse wire having great strength for withstanding strains in all directions, and to this outside wire covering are applied under heat successive coatings 5 6 6 sufficient to render the wire covering 5 impervious to moisture and absolutely current-proof, 6. a, so that electrolysis cannot take place.) Then aiinaloutside heavy layer 5 of my special compound is applied and the whole cable is vulcanized.

In generaLI prefer to make use of old agents and materials; but I compound them and arrange the successive steps and materials in such an order and relative position as to secure the new results desired.

WVhile I secure permanence of flexibility, high insulating qualities, and absolutely fireproof and waterproof qualities, the most important advantage secured by my invention is that it is electrolysis-proof, without, however, introducing any weakness or diminishing in any degree the fireproof, waterproof, insulating, and impervious character of the cable or conductor. The moisture-proof character of my conductor or cable is due to the fact that it is not an air-drying construction, but is chemically and mechanically built up into permanent integral condition in such a manner that it maintains substantially the same character throughout long use. The process of rendering the cable or conductor permanently flexible-and longitudinally strong, proof against electrolysis, and impervious to puncture, &c., is due to the employment of c1osely-braided wire coated under heat by successive dippings in the compound mentioned. This is one of the most important features of my process. Instead of lead pipe, which has very weak longitudinal strength, the braided Wire is employed with its great tensile strength, and instead of the lead, which invites attack by electrolysis, the electrolysis-proof compound is employed, and instead of fragile and brittle coverings which have been heretofore suggested on account of electrolysis I employ my compound in connection with the wire, Whichis permanently flexible, and instead of applying said compound as an independent layer which might be peeled off I unite it directly with the metal by the process of heat, and in the more complete carrying out of my process I vulcanize all the parts together, so that the cable or conductor assumes a homogeneous character throughout. This latter step in the process isalso of prime importance, especially when the article is to be subjected to severe usage. However, I do not undertake to enumerate herein all the features of novelty, as they are pointedout more at length in a concurrent application, where I have claimed the product as an article of manufacture.

Iwish it understood also that for certain pointed out in the claims, and still gain various advantages over what has heretofore been done, and also I wish it understood that I do not limit myself in all respects to the exact order and arrangement, except as otherwise stated in the following claims, where I have more particularly defined my invention, said claims being taken in connection with this description and the illustrativedrawings. By the term conductor-wire or conductor in the claims I mean to include any conducting means, whether consisting of an individual strand or of a plurality of strands or wires as commonly found in individual conductors or in cables and the like as used for light, heat, power, telephonic, and other purposes.

Having described my invention, what I claim as new, and desire to secure by Letters Patent of the United States, is-

1. The herein-described process, consisting of coating a conductor-wire with a cover of approximately pure rubber, applying to said rubber coating a plurality of vulcanizable coatings containing insulating and fireproofing ingredients, with increasing proportions of the latter in successive coatings, applying a Woven-wire jacket tightly thereto, applying a highly-heated, thin, vulcanizable, fireproof and electrolysis-proof insulating compound to said wire jacket, maintaining said jacket and the adjacent contained portions highly heated during said application, repeating said application of said thin compound a plurality of times until said compound has permeated the meshes of the jacket and become incorporated therewith entirely about the individual strands and on both sides of the jacket, said jacket being permitted to cool appreciably between successive applications of said compound, then applying a heavy coating of vulcanizable, lireproofing compound,and finally vulcanizing the whole together.

2. The herein-described process, consisting in providing a conductor-wire with vulcanizable insulation and then applying a metal jacket thereto, applying to said jacket a fireproof and electrolysis-proof insulating valcanizable, plastic compound, heating said compound and metal jacket during said application sufliciently to incorporate the compound in the jacket, and then permitting the same to cool and repeating said treatment, heating and cooling, until the metal jacket is covered with a thick coating and finally vulcanizing the whole together.

3. The hereindescribe ;l process, consisting in applying to a conductor-wire successive dippings of insulating and lireproofing compound, the first clippings consisting exclusively or principally of insulating material and the fireproof ingredients predominating in the outer dippings, said compound containing material for rendering the product permanently flexible and also containing a vulcanizing agent, next applying a fibrous covering permeated throughout With fireproof material, applying thereto a coating of vulcanizable fireproof and taining both the Wire covering and thin com pound highly heated during said clippings, and applying to the exterior a thick, permanently-flexible coating of vulcanizable compound containing insulating, fireproofing and Waterproofing ingredients, the latter two predominating, and finally vulcanizing the whole sufficiently to unite all of said parts together into a flexible, unitary article.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

AMANDA M. LOUGEE.

itnesses:

S. M. LAKE, H. J. SWAIN, 

